US4172221A - Circuit arrangement for automatically closing a switching transistor for a predetermined time period after opening a switching means - Google Patents

Circuit arrangement for automatically closing a switching transistor for a predetermined time period after opening a switching means Download PDF

Info

Publication number
US4172221A
US4172221A US05/798,009 US79800977A US4172221A US 4172221 A US4172221 A US 4172221A US 79800977 A US79800977 A US 79800977A US 4172221 A US4172221 A US 4172221A
Authority
US
United States
Prior art keywords
transistor
voltage
response
switch
radiation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/798,009
Other languages
English (en)
Inventor
Nobuyoshi Iizuka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Victor Company of Japan Ltd
Original Assignee
Victor Company of Japan Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Victor Company of Japan Ltd filed Critical Victor Company of Japan Ltd
Application granted granted Critical
Publication of US4172221A publication Critical patent/US4172221A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J40/00—Photoelectric discharge tubes not involving the ionisation of a gas
    • H01J40/02—Details
    • H01J40/14—Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/28—Modifications for introducing a time delay before switching

Definitions

  • the present invention relates to optically coupled switching circuits and more particularly to a circuit for automatically closing a switching transistor for a predetermined time period after opening a switching means.
  • Circuits for automatically closing a switching transistor for a predetermined interval after a switch has been opened are very useful for rewinding a magnetic tape of a magnetic tape recorder/player for a predetermined short time period after a reproduction mode thereof has closed.
  • a capacitor is used for such a purpose by employing its charging and discharging time constant.
  • the prior art is complicated and has poor reliability in that (1) an additional charging and discharging circuit is required and (2) the time change can not be negligible with respect to the electrical characteristic of the capacitor.
  • the present invention relates to a circuit for automatically closing a switching transistor for a predetermined time period after opening a switching means.
  • the circuit includes a radiation emissive element connected in series with said switch between first and second terminals of a DC voltage source.
  • the emissive element emits radiation in response to a first circuit condition of the switch.
  • Optically coupled to the emissive element is a radiation responsive element having a resistance which varies instantaneously from a normal value in response to receipt of the emitted radiation.
  • the radiation responsive element gradually returns to the normal value as a function of time when the emissive element is in a second condition of the switch.
  • the radiation responsive element is connected in series with a resistance element between the first and second voltage source terminals.
  • a transistor has a control electrode connected to be responsive to the voltage at a junction between the radiation responsive element and the resistance element.
  • the transistor assumes a first switching state when the voltage is below a predetermined threshold level and a second switching state when the voltage is above said threshold level. Thereby, there is a voltage transition in the circuit from a first to a second voltage level in response to the switch being switched to a second circuit condition. There is a transition of the voltage from the second to the first voltage level in response to the transistor assuming the second switching state.
  • the circuit is used with a reproduction control unit and a tape motor rewind control unit of a tape recorder/playback device.
  • the switch which controls energization of the radiation emitting means also controls the reproduction control unit so both are simultaneously energized and de-energized.
  • the voltage transition controls the rewind control unit so the motor is activated simultaneously with the reproduction control unit being energized by the switch means closure and the motor remains activated for a short time after the reproduction control unit is de-energized by opening of the switch means.
  • the single FIGURE is a schematic circuit diagram of a preferred embodiment of the present invention.
  • a circuit arrangement 8 embodying the present invention is described in connection with, by way of example, a reproduction control unit 4 and a rewind control unit 9 of a magnetic tape recorder/player however, circuit 8 is not limited to use with peripheral units 4 and 9.
  • Opto-electric coupler 3, connected between a pair of power supply lines 6 and 7, includes a photodiode 1 and a photosensitive resistor 2.
  • the anode and cathode of photo diode 1 are respectively connected to the line 6 through a resistor R1, and to the line 7 through suitable, normally open contact switching means S1.
  • Opposite ends of photosensitive resistor 2 are respectively connected to line 6 through variable resistor R2 and to line 7 through resistor R3.
  • the reproduction control unit 4 is connected between line 6 and switching means S1, whereby the magnetic tape recorder/player is activated into a reproduction mode only while switching means S1 is closed.
  • the base of switching transistor X1 is connected to a junction (no numeral) between resistor R2 and photosensitive resistor 2; the emitter and collector of transistor X1 are respectively connected to line 6 and to one end of resistor R4.
  • the other end of the resistor R4 is connected to a common terminal for the anodes of diodes D1 and D2.
  • the cathodes of diodes D1 and D2 are respectively connected to switching means S1 and to the base of switching transistor X2.
  • the emitter and the collector of the transistor X2 are respectively connected to the line 7 and to the base of the transistor X3 through a resistor R5.
  • Resistors R6 and R7 and a switching means S2 are connected in series between the lines 6 and 7.
  • a voltage at terminal 10 between resistors R6 and R7 is applied to the base of a transistor X3 for rendering the transistor X3 conductive at least when the switching means S2 closes.
  • the collector of the transistor X3 is connected to the line 7 through series connected resistors R8 and R9, having a common terminal 11 connected through resistor R10 to the base of transistor X4.
  • the collector of the transistor X4 is connected to line 6 through a rewind control means 5, such as a solenoid of a rewind motor (not shown); the emitter of transistor X4 is connected directly to line 7.
  • reproduction control unit 4 activates the magnetic tape recorder/player into reproduction mode as previously mentioned; simultaneously light-emitting diode 1 begins emitting a light beam toward photosensitive resistor 2.
  • resistor 2 When resistor 2 is irradiated by the light beam, its resistance is reduced instantaneously from a normal value to render transistor X1 conductive.
  • Current flowing through transistor X1 flows through the diode D1 and the closed switching means S1. Therefore, the voltage at the base of the transistor X2 is nearly equal to ground potential, so that the transistor X2 remains non-conductive.
  • the diode D2 compensates for a voltage drop across the diode D1, whereby the proper operation of the transistor X2 is ensured.
  • the reproduction control unit 4 When switching means S1 opens, the reproduction control unit 4 is de-energized, stopping the reproduction mode; at the same time, light-emitting diode 1 stops emitting the light beam. Therefore, the resistance of the photosensitive resistor 2 increases so that the voltage applied to the base of the transistor X1 rises.
  • the transient time of the resistance change of resistor 2 is about 0.5 second if a "CdS" cell is used as resistor 2; i.e., about 0.5 seconds is required for resistor 2 to be restored to a resistance 95% of its normal value.
  • the transistor X1 remains conductive for a predetermined time period after switching means S1 opens, until the resistance of resistor 2 increases to approximately its normal value. Since switching means S1 is open, current flowing through the emitter collector path of transistor X1 flows into the base of the transistor X2, rendering the same conductive.
  • the switching means S2 is in its open condition. If the transistor X2 is conductive, a current flows through the resistors R6 and R5, developing a suitable voltage for rendering transistor X3 conductive. Rendering of transistor X3 into a conductive state in turn causes transistor X4 to be conductive, so that rewind control means 5, such as the solenoid of the rewind motor (not shown), is energized to rewind the magnetic tape (not shown) only while the transistor X2 is conductive.
  • rewind control means 5 such as the solenoid of the rewind motor (not shown)
  • rewinding of the magnetic tape (not shown) is carried out until the voltage at the junction between the resistors R2 and 2 increases to a threshold level for conduction of transistor X1 after the light-emitting diode 1 is de-energized.
  • the rewinding time period (usually up to 0.2-0.3 seconds), which corresponds to 4-5 seconds under reproduction mode, is controlled by changing the resistance value of the variable resistor R2.
  • Switching means S2 while depressed is used for rewinding the magnetic tape and is not directly concerned with the present invention.
  • the light emitting diode 1 can be replaced by an incandescent lamp or a neon lamp and the photosensitive resistor 2 is a suitable element such as "CdS" or "CdSe” cell. If light emitting diode 1 is replaced by a light source, such as an incandescent lamp, having light emission which occurs after the source is deenergized, the photosensitive resistor 2 can be replaced by a high-speed photosensitive device, such as a photo-transistor.

Landscapes

  • Electronic Switches (AREA)
US05/798,009 1976-05-19 1977-05-18 Circuit arrangement for automatically closing a switching transistor for a predetermined time period after opening a switching means Expired - Lifetime US4172221A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP51/63630[U] 1976-05-19
JP6363076U JPS52155012U (enrdf_load_stackoverflow) 1976-05-19 1976-05-19

Publications (1)

Publication Number Publication Date
US4172221A true US4172221A (en) 1979-10-23

Family

ID=13234847

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/798,009 Expired - Lifetime US4172221A (en) 1976-05-19 1977-05-18 Circuit arrangement for automatically closing a switching transistor for a predetermined time period after opening a switching means

Country Status (2)

Country Link
US (1) US4172221A (enrdf_load_stackoverflow)
JP (1) JPS52155012U (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4577097A (en) * 1982-09-03 1986-03-18 The Babcock & Wilcox Company Three-mode analog controller with remote tuning
US4600847A (en) * 1984-12-24 1986-07-15 Gte Laboratories Incorporated Predistortion equalizing circuit
US4924081A (en) * 1987-09-22 1990-05-08 Minolta Camera Kabushiki Kaisha Photo-electric converter having offset voltage correcting function
US5850351A (en) * 1996-04-25 1998-12-15 General Motors Corporation Distributed management apparatus for battery pack
US6011329A (en) * 1998-08-28 2000-01-04 Mcgovern; Patrick T. Electrical circuit cycling controller
US20110315861A1 (en) * 2010-06-25 2011-12-29 Semiconductor Energy Laboratory Co., Ltd. Photoelectric conversion device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2416595A (en) * 1944-03-15 1947-02-25 Rca Corp Photoelectric relay
US3210611A (en) * 1962-05-11 1965-10-05 Westinghouse Electric Corp Light responsive switching circuit having time delayed operation
US3218462A (en) * 1961-11-29 1965-11-16 Ibm Direct current amplifier
US3308276A (en) * 1962-10-18 1967-03-07 Ibm Remote terminal
US3566132A (en) * 1967-12-26 1971-02-23 Gen Electric Beginning-of-tape and end-of-tape sensor

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5071304A (enrdf_load_stackoverflow) * 1973-10-25 1975-06-13
JPS50110553A (enrdf_load_stackoverflow) * 1974-02-08 1975-08-30

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2416595A (en) * 1944-03-15 1947-02-25 Rca Corp Photoelectric relay
US3218462A (en) * 1961-11-29 1965-11-16 Ibm Direct current amplifier
US3210611A (en) * 1962-05-11 1965-10-05 Westinghouse Electric Corp Light responsive switching circuit having time delayed operation
US3308276A (en) * 1962-10-18 1967-03-07 Ibm Remote terminal
US3566132A (en) * 1967-12-26 1971-02-23 Gen Electric Beginning-of-tape and end-of-tape sensor

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4577097A (en) * 1982-09-03 1986-03-18 The Babcock & Wilcox Company Three-mode analog controller with remote tuning
US4600847A (en) * 1984-12-24 1986-07-15 Gte Laboratories Incorporated Predistortion equalizing circuit
US4924081A (en) * 1987-09-22 1990-05-08 Minolta Camera Kabushiki Kaisha Photo-electric converter having offset voltage correcting function
US5850351A (en) * 1996-04-25 1998-12-15 General Motors Corporation Distributed management apparatus for battery pack
US6011329A (en) * 1998-08-28 2000-01-04 Mcgovern; Patrick T. Electrical circuit cycling controller
US20110315861A1 (en) * 2010-06-25 2011-12-29 Semiconductor Energy Laboratory Co., Ltd. Photoelectric conversion device
US9117958B2 (en) * 2010-06-25 2015-08-25 Semiconductor Energy Laboratory Co., Ltd. Photoelectric conversion device comprising photoelectric conversion element

Also Published As

Publication number Publication date
JPS52155012U (enrdf_load_stackoverflow) 1977-11-25

Similar Documents

Publication Publication Date Title
US4713819A (en) Semiconductor laser driver
US4628268A (en) Test device for testing an actuator circuit
CA1122663A (en) Protection circuit for transistorized switch
EP0405952B1 (en) Semiconductor laser driving circuit
US4172221A (en) Circuit arrangement for automatically closing a switching transistor for a predetermined time period after opening a switching means
US4417156A (en) Gate circuit for thyristors
US5831959A (en) Laser control circuit in recordable optical disk drive
US4277811A (en) Static type circuit breaker
US4401894A (en) Automatic uninterrupted D.C. power source switch
US4322637A (en) Solid state switch
US20220285116A1 (en) Current source contactor drives with economizers
JP2563250B2 (ja) 半導体レ−ザ駆動回路
JP2533535B2 (ja) 光ディスク装置
JP2623946B2 (ja) 電磁石装置の駆動回路
US4285586A (en) Camera controller for flashgun operation
JPS6258531A (ja) スイツチ駆動制御回路
JPS58151081A (ja) レ−ザ−電源回路
JPH04255284A (ja) レーザダイオードの駆動制御装置
JPS604284Y2 (ja) テ−プレコ−ダの録音表示装置
JP2736079B2 (ja) レーザ駆動回路
JPS5834643A (ja) 通信線路監視方式
JPS59223910A (ja) 磁気デイスク装置
JP2525386B2 (ja) レ−ザダイオ−ド駆動装置
JPS585210Y2 (ja) 自動平衡形ペン書き記録計
JPS5831206Y2 (ja) 電源装置